Currently, conventional PoP networking architecture has a two-layer or multi-layer hierarchy, and as shown in FIG. 1, is divided into different layers according to functions and deployment locations. For example, it can be divided into a core layer, a convergence layer, an edge access layer, and a peer layer. A dual-homing redundant connection is generally used between these layers to improve reliability, and converge and route user traffic layer by layer.
As network traffic and broadband users keep increasing, a carrier generally performs scale expansion once every one or two years. An expansion method mainly includes adding a PoP layer, increasing the number of devices, or changing a device platform capacity or a port capacity.
On a network, an access layer device is responsible for user traffic access, provides abundant user interface types, and features an extensive node distribution and a high port density; a convergence layer device is responsible for converging and routing access node traffic, expands a service coverage range of a core node, and features abundant port types, a powerful convergence capability, and a comprehensive service processing capability; and a core layer device is responsible for high-speed forwarding, interconnects and routes services between areas, and features a small number of nodes.
The PoP network architecture shown in FIG. 1 is formed by various devices, and a dual-homing interconnection between these devices occupies a large number of physical ports. Therefore, device port resources and energy are seriously wasted, and the more layers are converged, the more device port resources and energy are wasted. In this type of network architecture, many network devices exist and have various types and service capabilities, and therefore the topology structure is complicated. This results in difficult service convergence and expansion, complex configuration, high system overhead, and poor global coordination. In addition, deployments of the security, OAM, reliability, and QoS are complex and unsmooth. The more layers are converged, the more internal forwarding hops are, which results in slow routing convergence, a poor routing stability, and difficult fault management.
As the network scale, traffic, and user quantity keep increasing, more PoP points exist on an IP bearer network, the network becomes denser, and a degree of interconnection becomes higher. Therefore, the network structure needs to be integrated and simplified to improve a resource utilization, reduce a cost, reduce energy consumption, lower management complexity, and improve routing convergence and stability.
In the prior art, a virtual switching system (VSS, virtual switching system) exists. On this system, two physical switches constitute one virtual switch, and control and management planes are centralized in one of the physical switches. This system is mainly provided for two or more master switching devices at a same network layer and is applicable to a simple chain or ring topology. However, this virtual switching system has no application for a tunnel.